Hypothetical Performance

[Overkill338]

How much speed do you think you would lose by shortening the RUM case down to 2.50" like a 7mm Rem Mag, or .338 Win Mag? For comparison the WSM cases are 2.1". I believe it might better the STW by 100+ fps, but fit in even a Ruger Long Acrion.

 

[Mram10us]

A 33 nosler is about that size. So, I'll guess 75fps with a 300 gr.

 

[Overkill338]

A 33 nosler is about that size. So, I'll guess 75fps with a 300 gr.

Well there is another one of my dreams shot down. I need to quit flying my ideas in the Hindenburg.

 

[Mram10us]

Well there is another one of my dreams shot down. I need to quit flying my ideas in the Hindenburg.

Actually, your idea is much better than the 33 nosler! You have .040" more room for powder and it still works in a normal long action Call it the 33creed..... nevermind

 

[tdot]

How much speed do you think you would lose by shortening the RUM case down to 2.50" like a 7mm Rem Mag, or .338 Win Mag? For comparison the WSM cases are 2.1". I believe it might better the STW by 100+ fps, but fit in even a Ruger Long Acrion.

What Caliber?

In 308 Caliber, that would be similar to a 300PRC cartridge.

 

[Overkill338]

Actually, your idea is much better than the 33 nosler! You have .040" more room for powder and it still works in a normal long action Call it the 33creed..... nevermind

I just want to rebarrel my Ruger MKII, and someone suggested short mags. That got me to thinking, why not make them a little longer? Thank you for the kind words, sorry I misunderstood you the first time. I'm attaching my rough sketch drawing. I'm not artist so it is definitely not pretty drawing lol

What Caliber?

In 308 Caliber, that would be similar to a 300PRC cartridge.

I haven't set that in stone. Orginally I was thinking .338, but it may be a .284", and also, the idea of a .366" seems interesting as well. I'm open to thoughts.

 

[Mram10us]

All good, Sir. The 7mm rum was interesting but when they shortened the case, making a 28 nosler, I fell in love. Nothing better than a big fat case that sits bullets long and still feeds from a normal magazine box.

 

[Overkill338]

All good, Sir. The 7mm rum was interesting but when they shortened the case, making a 28 nosler, I fell in love. Nothing better than a big fat case that sits bullets long and still feeds from a normal magazine box.

A fella ran my .338 in Quickload, he did not exceed 100% capacity.
225gr bullet, 83.6gr of RL26
24" - 2880
26" - 2934
28" - 2983

I think that seems pretty darn good, but doesn't a .338 Win Mag do the same thing?

 

[tdot]

A fella ran my .338 in Quickload, he did not exceed 100% capacity.
225gr bullet, 83.6gr of RL26
24" - 2880
26" - 2934
28" - 2983

I think that seems pretty darn good, but doesn't a .338 Win Mag do the same thing?

My max load in a 338ss is over 2900 with a 213 grain in. 22" barrel. That's roughly 62 grains of Varget or H4895. Longer barrel and a slower powder, I'm sure it'd be over 3000. The 338WM doesnt beat the 338ss by much, if anything at all, and certainly not in a short barrel.

 

[tdot]

I just want to rebarrel my Ruger MKII, and someone suggested short mags. That got me to thinking, why not make them a little longer? Thank you for the kind words, sorry I misunderstood you the first time. I'm attaching my rough sketch drawing. I'm not artist so it is definitely not pretty drawing lol

View attachment 162804



I haven't set that in stone. Orginally I was thinking .338, but it may be a .284", and also, the idea of a .366" seems interesting as well. I'm open to thoughts.

If you haven't already, look at the Sherman Wildcats, the MAX cartridges are essentially blown our and lengthened SAUM's. That may get you to where you're thinking.

 

[FURMAN]

I am a little confused about your question, you are basically describing the Nosler family of cartridges. Very little if anything will be gained by shortening the 28 and 30 the very little to get the the exact 2.5" and as pointed out the 33 is already a little under. As far as loss it really depends on bullet weights. Large overbore cartridges really need heavy for caliber bullets to realize the cartridge potential. I personally don't feel there are big enough bullets in 7mm for this which is why the 28 Nosler shines and cartridges like the 7-300 Win will almost match the 28 with a lot less powder. The 300 Rum is almost in the same boat but can start to distance itself from the 30 Nosler with 230s and the newer 245 and 250 bullets will widen the gap but then you are limited by several other factors unless you are ok with a single shot.

 

[LongBomber]

A fella ran my .338 in Quickload, he did not exceed 100% capacity.
225gr bullet, 83.6gr of RL26
24" - 2880
26" - 2934
28" - 2983

I think that seems pretty darn good, but doesn't a .338 Win Mag do the same thing?

Thats basically right where I am at with the 33N in a 26" barrel.

Now a 375 that is based on a 2.5" case. Possible to load some of the high bc 375 bullets and still be a repeater in a standard 700 long action?

 

[25WSM]

I almost made the same thing about 6 years ago. I built my friend a smoking 300Rum and as we played around with it I just kept telling myself that's just too much case for the 30. I told him I want to make one for myself but I want mine to be the length of the 338. So basically a 30-338 Rum. It just seems to me Remington should have put the 7mm and 30 on the shorter rum case and then make the 338 on the 300 case. I never made one because the wsm seemed to be all I needed. I'm really impressed with the new Hornady cartridges. I was a hater. I was never Creed. Hornady was pretty much rock bottom on my list for components and tools and bullets. My friend from the 1000 yard matches wanted a 6.5 Creed and he even convinced me to try it also. We have won relays and match's with them and one weekend we both won our relay for group and score. You only get the win in group but it's cool when you get both. So I went from hater to wow there really is something there. Just look at the new PRC. They made it fit in actions with room for the bullets. That's basically it. The same thing the Creed is. 6.5 Creed vs 260. This is about as close to an answer I can give the op. Let's move the shoulder back so bullets sit in the neck properly and fit in the intended mag length. We lost some capacity in the case. We made it more efficient. We made it fit. And the performance loss is minimal. Yes the 260 can beat the Creed loaded long and the bigger 30s are going to outrun the 300 PRC. Capacity wins in the speed catagory. To the op if the slight loss in velocity is ok with your goal, then make it what you want it to be. As of now it seems that short mags and middle mags and long mags are here to stay.
Shep

 

[tdot]

Thats basically right where I am at with the 33N in a 26" barrel.

Now a 375 that is based on a 2.5" case. Possible to load some of the high bc 375 bullets and still be a repeater in a standard 700 long action?

After seeing a 375 Cheytac cartridge (is that the Snipetac?). I thought it would be fun to trim a 338 Lapua case down to a shorter length, necked to 375. Setup to magazine feed in a long action... I never looked into it enough to understand the nuances of the larger bolt face and how far it would have to be trimmed. But the idea of a 375 Short Mag, just seemed awesome. Hopefully gain the efficiency of the short fat powder column. But really we just had a bison tag at the time and I was thinking of fun/effective ways to prepare and hunt him.